Tag: science

Parker to make its last fly-by of Venus

9:33 am

The Parker Solar Probe is scheduled to complete its last fly-by of Venus on November 6, 2024, passing only 233 miles above the planet’s surface.

The flyby will adjust Parker’s trajectory into its final orbital configuration, bringing the spacecraft to within an unprecedented 3.86 million miles of the solar surface on Dec. 24, 2024. It will be the closest any human made object has been to the Sun.

That close solar approach will occur on December 24, 2024. Whether the spacecraft can survive is the main question, and we won’t find out until three days later, when it sends a signal to confirm its survival. If successful, it will then attempt to repeat that close fly-by at least two more times.

As for the Venus fly-by, the spacecraft will use one instrument to attempt to peer into Venus’s clouds.

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WISE/NEOWISE burns up in the atmosphere

9:22 am

NASA’s Wide-field Infrared Survey Explorer (WISE, later renamed NEOWISE) has ended its fifteen years in orbit, burning up in the atmosphere on November 1, 2024.

In its initial mission it did an infrared survey of the sky, discovering millions of black holes, many of the most luminous galaxies, and numerous brown dwarfs. It was then repurposed to survey the sky for near Earth objects, asteroids that have the potential to impact the Earth, discovering more than two hundred new asteroids while tracking more precisely another 3,000. It did this by repeating its survey over and over so that moving objects could be spotted.

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Sunspot update: in October solar activity increased after September’s crash

3:35 pm

Time for this month’s sunspot update. As I have done every month since I started this website in 2010, I am posting NOAA’s most recent update of its monthly graph tracking the number of sunspots on the Sun’s Earth-facing hemisphere, adding some additional details to provide context.

In October, following a crash in activity in September, the Sun showed a slight increase the number of sunspots. The increase did not match the drop from the month before, but it brought the activity back up to the level seen during the summer.
» Read more

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A 2017 supernova as spotted by Hubble

11:20 am

Before and after of galaxy with supernova
Click for original image.

Cool image time! The pictures to the right were both compiled from photos taken by the Hubble Space Telescope, with the bottom annotated to indicate the location of a 2017 supernova that was not visible in the earlier 2005 picture.

In this collage two images of the spiral galaxy NGC 1672 are compared: one showing supernova SN 2017GAX as a small green dot, and the other without. The difference between the images is that both have been created by processing multiple individual Hubble images, each taken to capture a specific wavelength of visible light, and combining them to make a full-colour image. In one of those filtered frames, taken in 2017, the fading supernova is still visible

NGC 1672 is considered a barred spiral galaxy. Located an estimated 52 million light years away, the 2017 supernovae was not the last detected within it. In 2022 a second supernovae occurred. That’s two supernovae within five years. Meanwhile the Milky Way has not seen a supernova in more than four centuries.

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Another model proposed for explaining flowing liquid water in the distant Martian past

2:35 pm

New model for explaining flowing water on Mars
Click for full resolution graphic.

A new model has now been proposed for explaining how liquid water could have once flowed on Mars and created the many channels and river-like features geologists see today.

This new theory posits that the carbon dioxide in the atmosphere, once thicker, fell as snow to bury water ice on the surface near the poles, where that ice then melted from pressure and heat from below to flow underground and then out into lower latitudes.

The paper, led by Planetary Science Institute Research Scientist Peter Buhler, describes how 3.6 billion years ago, carbon dioxide froze out of Mars’ atmosphere and deposited on top of a water ice sheet at the poles, insulating heat emanating from Mars’ interior and increasing the pressure on the ice. This caused roughly half of Mars’ total water inventory to melt and flow across its surface without the need for climatic warming.

The graphic to the right is figure 1 from Buhler’s paper. It shows this process in the south pole, flowing north through Argyre Basin and along various now meandering channels to eventually flow out into the northern lowland plains. In every case Buhler’s model posits the water flowed in “ice-covered rivers” or “ice-covered lakes”, the ice protecting the water so that it could flow as a liquid.

This model confirms once again my impression that the Mars planetary community is increasingly considering glaciers and ice as a major past factor in shaping the planet we see today. This model suggests liquid water under ice, but it still remains possible that ice alone could have done the job.

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A somewhat typical but strange crater in Mars’ Death Valley

1:57 pm

A somewhat typical crater in Mars' death valley
Click for original image.

Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on August 29, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The camera team labels the primary feature in this picture as “ridges,” but what I see is a strange crater that at first glance appears to be impact-caused, but at closer inspection might be something else entirely.

This unnamed crater is about one mile wide. It is only about fifty feet deep, but sits above the surround landscape by about 200 feet. That high position suggests strongly that this crater was not formed by an impact by is instead a caldera from some sort of volcanic activity, with the splash apron around it simply examples of past magma flows erupting from within.

The ridges inside the crater might be glacial debris, as this location is at 35 degrees south latitude, making near surface ice possible.
» Read more

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Scientists use Hubble and Webb to confirm there are as yet no planets forming in Vega’s accretion disk

11:16 am

Hubble and Webb images of Vega's accretion disk
Click for original image.

Using both the Hubble and Webb space telescopes, scientists have now confirmed, to their surprise, that the accretioni disk that surrounds the nearby star Vega is very smooth with almost no gaps, and thus apparently has not new exoplanets forming within it.

The two pictures to the right, cropped and reduced to post here, come from two different papers. The Hubble paper is here [pdf] while the Webb paper is here [pdf]. From the press release:

Webb sees the infrared glow from a disk of particles the size of sand swirling around the sizzling blue-white star that is 40 times brighter than our Sun. Hubble captures an outer halo of this disk, with particles no bigger than the consistency of smoke that are reflecting starlight.

The distribution of dust in the Vega debris disk is layered because the pressure of starlight pushes out the smaller grains faster than larger grains. “Different types of physics will locate different-sized particles at different locations,” said Schuyler Wolff of the University of Arizona team, lead author of the paper presenting the Hubble findings. “The fact that we’re seeing dust particle sizes sorted out can help us understand the underlying dynamics in circumstellar disks.”

The Vega disk does have a subtle gap, around 60 AU (astronomical units) from the star (twice the distance of Neptune from the Sun), but otherwise is very smooth all the way in until it is lost in the glare of the star. This shows that there are no planets down at least to Neptune-mass circulating in large orbits, as in our solar system, say the researchers.

At the moment astronomers consider the very smooth accretion disk surrounding Vega to be rare and exception to the rule, with most debris disks having gaps that suggest the presence of newly formed exoplanets within them. That Vega breaks the rule however suggests the rule might not be right in the first place.

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Weird ring-mounds in one of Mars’ largest craters

3:03 pm

Weird ring mounds on Mars
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on August 16, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The science team labels these strange features “ring-mound landforms,” a term that has been used to describe [pdf] only vaguely similar features previously found in the Athabasca flood lava plain almost on the other side of Mars. That paper suggested that those ring mounds formed on the “thin, brittle crust of an active fluid flow” created by an explosive event. Since Athabasca is considered Mars’s most recent major flood lava event, the fluid was likely lava, which on Mars flows more quickly and thinly in the lower gravity.

Thus, in Athabasca the ring-mounds formed when a pimple of molten lava from below popped the surface.

But what about the ring mounds in the picture to the right?
» Read more

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Post-collision images of two galaxies

10:56 am

Post-collision imagery by Hubble and Webb
Click for original image.

Using both the Hubble and Webb space telescopes, astronomers have now produced multi-wavelength images of the galaxies NGC 2207and IC 2163, as shown to the right.

Millions of years ago the smaller galaxy, IC 2163, grazed against the larger, NGC 2207, resulting today in increased star formation in both galaxies, indicated by blue in the Hubble photo. From the caption of the combined images:

Combined, they are estimated to form the equivalent of two dozen new stars that are the size of the Sun annually. Our Milky Way galaxy forms the equivalent of two or three new Sun-like stars per year. Both galaxies have hosted seven known supernovae, each of which may have cleared space in their arms, rearranging gas and dust that later cooled, and allowed many new stars to form.

The two images to the left leaves the Hubble and Webb separate, making it easier to see the different features the different wavelengths reveal. From this caption:

In Hubble’s image, the star-filled spiral arms glow brightly in blue, and the galaxies’ cores in orange. Both galaxies are covered in dark brown dust lanes, which obscure the view of IC 2163’s core at left. In Webb’s image, cold dust takes centre stage, casting the galaxies’ arms in white. Areas where stars are still deeply embedded in the dust appear pink. Other pink dots may be objects that lie well behind these galaxies, including active supermassive black holes known as quasars.

The largest and brightest pink area in the Webb image, on the bottom right and a blue patch in the Hubble image, is where a strong cluster of star formation is presently occurring.

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“What the heck?” lava on Mars

1:47 pm


Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on August 19, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled merely as a “terrain sample,” it was likely snapped not for any specific research project, but to fill a gap in the camera schedule in order to maintain its proper temperature.

When the science team does this they try to pick interesting locations. Sometimes the picture is relatively boring. Sometimes, like the picture to the right, it reveals weird geology that is somewhat difficult to explain. The picture covers the transition from the smooth featureless plain to the north, and the twisting and complex ridges to the south, all of which are less than a few feet high.

Note the gaps. The downgrade here is to the west, and the gaps appear to vaguely indicate places where flows had occurred.
» Read more

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Arecibo telescope collapsed because of a surprising engineering failure that inspections still should have spotted

1:41 pm

Illustration of cable failure at Arecibo

According to a new very detailed engineering analysis into the causes of the collapse of the Arecibo radio telescope in Puerto Rico in 2020, the failure was caused first by a surprising interaction between the radio electronics of Arecibo and the traditional methods used to anchor the cables, and second by a failure of inspections to spot the problem as it became obvious.

The surprising engineering discovery is illustrated to the right, taken from figure 2-6 of the report. The main antenna of Arecibo was suspended above the bowl below by three main cables. The figure shows the basic design of the system used to anchor the cable ends to their sockets. The end of the cable bunches would be inserted into the socket, spread apart, and then zinc would be poured in to fill the gap and then act as a plug and glue to hold the cables in place. According to the report, this system has been used for decades in many applications very successfully.

What the report found however was at Arecibo over time the cable bunch and zinc plug slowly began to pull out of the socket, what the report labels as “zinc creep.” This was noted by inspectors, but dismissed as a concern because they still believed the engineering margins were still high enough to prevent failure at this point. In fact, this is exactly where the structure failed in 2020, with the first cable separating as shown in August 2020. The second cable did so in a similar manner in November 2020.

The report concluded that the “only hypothesis the committee could develop that provides a plausible but unprovable answer to all these questions and the observed socket failure pattern is that the socket zinc creep was unexpectedly accelerated in the Arecibo Telescope’s uniquely powerful electromagnetic radiation environment. The Arecibo Telescope cables were suspended across the beam of ‘the most powerful radio transmitter on Earth.'”

The report however also notes that the regular engineering inspections of the telescope had spotted this creep, which was clearly unusual and steadily becoming significant, and did not take action to address the issue when it should have. It also noted the slow response of the bureaucracy, not only to the damage caused earlier to the facility by Hurriane Maria in 2017, but to obtaining the funding for any repairs.

Ray Lugo [the principal investigator for Arecibo] described to the committee how months of his time during 2018 were spent writing, resubmitting, and justifying repair funding proposals. Repairs had to go through the traditional “bid and proposal” process, described in more detail below, which added years of delay.

We can forgive the inspectors somewhat for not noting the creep when they should, as its cause appears to be very unusual, still uncertain and rare, but the red tape that prevented proper and quick repair effort after the hurricane is shameful. Had the telescope gotten the proper support on time, the creep itself might have even been addressed, because the resources would have been there to deal with it.

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Lab tests suggest water brines could also exist on large asteroids

12:28 pm

Gullies in crater on Vesta
Click for original image.

In attempting to explain the existence of flow features that have been found on the interior walls of craters on the asteroids Ceres and Vesta — as shown in the image above — scientists recently performed a laboratory experiment which determined that a mixture of water and salt could produce those gullies.

The team modified a test chamber at the Jet Propulsion Laboratory to rapidly decrease pressure over a liquid sample to simulate the dramatic drop in pressure as the temporary atmosphere created after an impact on an airless body like Vesta dissipates. According to Poston, the pressure drop was so fast that test liquids immediately and dramatically expanded, ejecting material from the sample containers.

“Through our simulated impacts, we found that the pure water froze too quickly in a vacuum to effect meaningful change, but salt and water mixtures, or brines, stayed liquid and flowing for a minimum of one hour,” said Poston. “This is sufficient for the brine to destabilize slopes on crater walls on rocky bodies, cause erosion and landslides, and potentially form other unique geological features found on icy moons.”

The press release makes it sound as if this result makes the existence of subsurface water ice more likely on such asteroids as Ceres and Vesta, but previous research from the Dawn asteroid probe made that fact very clear, especially for Ceres, years ago. All this does is provide some evidence of what might be one process by which these erosion gullies form.

Hat tip to reader Milt.

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Perseverance looks across Jezero Crater from on high

11:11 am

Panorama of Jezero Crater
Click for full resolution annotated image. Click here for unannotated full resolution image.

Cool image time! The panorama above, cropped, reduced, and sharpened to post here, was assembled from 44 pictures taken by the rover Perseverance on September 27, 2024 as it began its climb up the rim of Jezero Crater. If you click on it you can see the full resolution image that is also annotated to identify features within the crater as well as places where Perseverance has traveled.

The overview map below, with the blue dot showing the rover’s location when this panorama was taken. The yellow lines indicate the area covered by the panorama, with the arrow indicating the direction.

Overview map
Click for interactive map.

According to the information at the link, the rover has been experiencing some slippery sandy ground as it has been climbing.
» Read more

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Two cubesats on Hera signal home

10:07 am

Engineers on the ground have now established good communications with the two cubesats that are being carried by the European probe Hera on its way to the binary asteroids Didymos and Dimorphos.

“Each CubeSat was activated for about an hour in turn, in live sessions with the ground to perform commissioning – what we call ‘are you alive?’ and ‘stowed checkout’ tests,” explains ESA’s Hera CubeSats Engineer Franco Perez Lissi.

…Travelling with Hera are two shoebox-sized ‘CubeSats’ built up from standardised 10-cm boxes. These miniature spacecraft will fly closer to the asteroid than their mothership, taking additional risks to acquire valuable bonus data.

Juventas, produced for ESA by GOMspace in Luxembourg will make the first radar probe within an asteroid, while Milani, produced for ESA by Tyvak International in Italy, will perform multispectral mineral prospecting.

This use of small cubesats in conjunction with a larger interplanetary probe is becoming increasingly routine, and provides a cheap and efficient way to increase the data and information obtained. Note too that both cubesats were apparently built entirely by private companies, thus establishing their creditionals as providers of interplanetary probes.

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New issue with Voyager-1

9:41 am

The Voyager missions
The routes the Voyager spacecraft have
taken since launch.

According to a NASA report yesterday, engineers are dealing with a new technical problem that has occurred Voyager-1, flying out beyond the edge of the solar system.

On Oct. 16, the flight team sent a command to turn on one of the spacecraft’s heaters. While Voyager 1 should have had ample power to operate the heater, the command triggered the fault protection system. The team learned of the issue when the Deep Space Network couldn’t detect Voyager 1’s signal on Oct. 18.

The spacecraft typically communicates with Earth using what’s called an X-band radio transmitter, named for the specific frequency it uses. The flight team correctly hypothesized that the fault protection system had lowered the rate at which the transmitter was sending back data. This mode requires less power from the spacecraft, but it also changes the X-band signal that the Deep Space Network needs to listen for. Engineers found the signal later that day, and Voyager 1 otherwise seemed to be in a stable state as the team began to investigate what had happened.

Then, on Oct. 19, communication appeared to stop entirely. The flight team suspected that Voyager 1’s fault protection system was triggered twice more and that it turned off the X-band transmitter and switched to a second radio transmitter called the S-band. While the S-band uses less power, Voyager 1 had not used it to communicate with Earth since 1981. It uses a different frequency than the X-band transmitters signal is significantly fainter. The flight team was not certain the S-band could be detected at Earth due to the spacecraft’s distance, but engineers with the Deep Space Network were able to find it.

Though communications with the spacecraft continue, no data can be downloaded and work is essentially suspended while engineers troubleshoot why Voyager-1 kept initiating its fault system.

It is amazing that communications were still possible using the S-band after more than forty years. I would bet that no engineers from then still work at the Deep Space Network. Kudos to the engineers there now for finding the signal.

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NASA picks nine lunar south pole candidate sites for Artemis-3 manned landing

10:37 am

The Moon's south pole, with candidate landing sites
Click for NASA’s original image.

NASA today revealed the nine candidate sites in the Moon’s south polar region for its Artemis-3 manned mission, presently targeting a 2026 launch date.

The map to the right shows the location of those nine sites, numbered in order of priority, as follows:

  • 1. Peak near Cabeus B
  • 2 . Haworth
  • 3. Malapert Massif
  • 4. Mons Mouton Plateau
  • 5. Mons Mouton
  • 6. Nobile Rim 1
  • 7. Nobile Rim 2
  • 8. de Gerlache Rim 2
  • 9. Slater Plain

The map also shows the planned landing sites for Intuitive Machine’s Athena lander in January 2025, and China’s Chang’e-7 lander in 2026, as well as where India’s Virkam lander touched down in 2023.

Cabeus B is likely the prime candidate site because its high elevation will make communciations easier, while placing it closer to the crater Cabeaus, which was impacted by the LCROSS mission in 2009 and found a significant signature of water in the ejecta plume of that impact.

To make a final decision NASA will be consulting all players, from the science community as well as the engineers. All of this however depends on other factors outside of science and engineering, mostly related to politics and practicality. The entire mission relies on the full version of the SLS rocket, the manned lunar version of SpaceX’s Starship, launched by Superheavy, and a working version of Lockheed Martin’s Orion capsule, none of which are presently flightworthy.

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ISRO head unveils new timeline for major missions

10:06 am

The head of India’s space agency ISRO, S. Somanath, yesterday unveiled a new timeline for several of that nation’s major missions, both manned and unmanned.

The new timeline is as follows:

  • 2025: NISAR: a joint Indian-American radar orbiter, long delayed
  • 2026: Gaganyaan-1, India’s first manned orbital mission
  • 2028: Chandrayaan-4, an unmanned sample return mission to the Moon
  • 2028: Chandrayaan-5, a joint lander-rover to the Moon

The last project will be done in partnership with Japan, with India building the lander and Japan the rover.

2028 will be a very busy year for India in space. The Indian government had previously announced that ISRO would launch in 2028 the first module of its space station as well as a Venus orbiter.

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Unidentified astronaut from recent ISS mission released from hospital

9:54 am

Though NASA’s press release provided little informationto protect the astronaut’s privacy, including his or her name, the unidentified astronaut who was held overnight for observation after returning from a seventh-month stay on ISS mission has now been released from the hospital.

After an overnight stay at Ascension Sacred Heart Pensacola in Florida, the NASA astronaut was released and returned to NASA’s Johnson Space Center in Houston Saturday. The crew member is in good health and will resume normal post-flight reconditioning with other crew members.

This has happened before. Readapting to a 1G environment after months in weightlessness can be difficult, even if one does all the exercises required while in orbit.

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Using spectroscopic data, astronomers create 3D map of ancient supernova remnant

10:55 am

Supernova 1181
Click for original image.

Astronomers have now createdsdft a 3D map of the remnant formed by a supernova that occurred in 1181, using detailed spectroscopic data to determing which remnant filaments are moving towards us and which are moving away.

The picture to the right is from figure 1 of their paper, and shows how the filaments radiate out from the center in straight lines, something that is unusual for such remnants. It was taken in 2023 by a ground-based telescope at Kitt Peak in Hawaii. From simple optical data it is impossible however to determine which filaments are in the rear, expanding away from us, and which are in the front, expanding towards us.

To probe the three-dimensional structure of the supernova remnant, the astronomers turned to KCWI, an instrument that can capture multiwavelength, or spectral, information for every pixel in an image. This is like breaking apart the light captured in every pixel into a rainbow of colors. The spectral information enabled the team to measure the motions of the filaments poking out from the center of the explosion and ultimately create a 3D map of the structure. The filament material that is flying toward us shifted toward the blue higher-energy portion end of the visible spectrum (blue-shifted), while light from material moving away from us shifted toward the red end of the spectrum (red-shifted).

…The results showed that the filament material in the supernova is flying outward from the site of the explosion at approximately 1,000 kilometers per second. “We find the material in the filaments is expanding ballistically,” says Cunningham. “This means that the material has not been slowed down nor sped up since the explosion. From the measured velocities, looking back in time, you can pinpoint the explosion to almost exactly the year 1181.”

The 3D information also revealed a large cavity inside the spindly, spherical structure in addition to some evidence that the supernova explosion of 1181 occurred asymmetrically.

Using this data, they were able to create that 3D map, shown below in a coarse animation video.
» Read more

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The uncertainty of science: New research suggests first image in ’22 of Milky Way’s central black hole is likely not accurate

10:25 am

Sagittarius A*
The original interpretation. Click for full image.

The new interpretaion
The new asymmetrical interpretation. Click for original image.

Surprise, surprise! A new analysis of the data behind the 2022 false-color radio image of the supermassive black hole at the center of the Milky Way, posted to the right, suggests that image was not accurately interpreted from the data.

Astronomers led by the National Astronomical Observatory of Japan (NAOJ) say their analysis points at Sagittarius A* having an elongated accretion disk, as opposed to the ring-like “doughnut” image released in 2022 by an international team called the Event Horizon Telescope (EHT) collaboration.

The EHT image shows a central dark region where the hole resides, circled by the light coming from super-heated gas accelerated by immense gravitational forces.

But a new paper published today in Monthly Notices of the Royal Astronomical Society suggests that part of this appearance may actually be an artefact because of the way the image was put together. … Assistant professor Miyoshi Makoto, of the NAOJ, said: “Our image is slightly elongated in the east-west direction, and the eastern half is brighter than the western half. We think this appearance means the accretion disk surrounding the black hole is rotating at about 60 per cent of the speed of light.” He added: “Why, then, did the ring-like image emerge? Well, no telescope can capture an astronomical image perfectly. We hypothesise that the ring image resulted from errors during EHT’s imaging analysis and that part of it was an artefact, rather than the actual astronomical structure.”

It must be noted that this false color radio image was assembled from eight different radio telescopes across the globe, and to bring the data together required a great deal of massaging. While most astronomers appear to favor the top picture, it is just as likely that the bottom picture is a better representation. Either way, both must be considered in any future studies of Sagittarius A*’s environment and structure.

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JPL unveils website for viewing all high resolution imagery so far taken of Europa

9:29 am

In anticipation of the eventual arrival of Europa Clipper in orbit around Jupiter to begin its close investigation of that planet’s moon Europa, JPL yesterday unveiled a website that allows a view to quickly find and review all the high resolution imagery so far taken of Europa by the Jupiter orbiters, Voyager, Galileo, and Juno.

You can visit the Europa Trek portal website here.

The announcement touts the webpage’s ability to take viewers on “fly-overs” of the terrain, but that’s just a bell and whistle claim of little importance. More significant is the easy access this webpage provides to all that imagery, organized in context with a global map of the planet. Not only can anyone quick find interesting features, you can do so within the global context of the whole planet. In addition, the page provides detailed commentary about each image.

When Europa Clipper arrives this portal will be invaluable in deciphering the significance of every new image and datapoint.

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A pointy mesa once washed by theorized Martian ocean

11:09 am

A pointy mesa on Mars
Click for original image.

Today’s cool image returns to the same region yesterday’s cool image visited. The picture to the right, cropped, reduced, and sharpened to post here, was taken on July 21, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It was clearly taken to get a close look at this unusual pointy mesa.

MRO elevation data says this mesa is about 800 feet height. The color difference between the north and south flanks suggests the accumulated presence of dust on the north, suggesting the prevailing winds here come from the northeast and blow to the southwest. This conclusion is reinforced by the dark accumulated dust found in the southwest quadrants of all the crater floors in the full image. The wind blows this dust into the craters, where it gets trapped against the southwest crater wall.

Note the mesa’s wide base, with one crater partly eaten away on its eastern edge. The overall shape of this base suggests that it was carved by some flow coming from the southwest, as indicated by the arrow.
» Read more

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The obvious visual evidence for assuming Mars once had catastrophic floods

12:03 pm

The obvious visual evidence of past catastropic floods on Mars
Click for original image.

Since the first comprehensive orbital data of Mars was sent back in the early 1970s by Mariner 9, scientists have generally concluded that many of the features seen at the eastern end of the giant Valles Marineris canyon were caused by one or several catastrophic floods.

The picture to the right, rotated, cropped, and reduced to post here and taken on July 26, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), provides a good example of why the scientists have come to that conclusion. It shows what the camera team labels a “streamline feature surrounding crater.” I have added the arrows to indicate the presumed direction of flow. The flow went around this 2.5-mile-wide unnamed crater because the impact had compacted it, making it resistent to erosion. The flow however was strong and large enough to wash away the plateau on which the crater sits, as well as cutting into the crater’s southwest rim. In addition, the rim on the southeast was also cut through at some point, this time from what might have been flow eddies as the flood pushed past.

Hence, the theory of catastrophic floods.

» Read more

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SpaceX asks FCC for license revision for launching nearly 30,000 Starlink satellites

8:51 am

SpaceX on October 11, 2024 submitted a request to the FCC to revise its Starlink satellite license to cover a revised plan for its second generation satellites that includes a request to place 29,988 Starlink satellites in orbit.

SpaceX first requests several amendments to the orbital parameters of its Gen2 system between 340 km and 365km altitude to keep pace with rapidly evolving global demand for high-quality broadband. First,SpaceX amends the inclination of its orbital shell at a nominal altitude of 345 km from 46 degrees to 48 degrees. SpaceX also amends its pending Gen2 application to seek authority to operate satellites in its Gen2 system in two additional orbital shells — at 355 km altitude in a 43-degree inclination and at 365 km altitude in a 28- or 32-degree inclination. The total number of operational satellites will remain 29,988 satellites across the amended Gen2 system.

With the exception of its polar shell at 360 km, which will remain unchanged, SpaceX also amends its application to more flexibly distribute satellites in its shells between 340 km and 365 km than requested in its pending application, specifically, in up to 72 planes per shell and up to 144 satellites per plane. While this reconfiguration will result in two additional shells and a higher maximum number of orbital planes and satellites per plane for all but one shell between 340 km and 365 km, the total number of operational satellites in the Gen2 system will remain 29,988 satellites.

In the company’s previous request for this number of satellites, the FCC had approved only 7,500, the full request still pending. We can expect objections from the other big satellite constellations to this request. The FCC’s response remains unclear. There could be legitimate reasons to limit SpaceX request, but it is also possible politics will enter the decision as well, for illegitimate reasons.

Meanwhile, astronomers are already whining about the problems these Starlink satellites will cause to their ground-based telescopes. It seems these so-called brilliant scientists can’t get it through their heads that astronomy from Earth will become increasingly difficult in the coming years — with hundreds of thousands of satellites planned from many satellite constellations, not just SpaceX — while astronomy from space has always been a better choice anyway. Rather than demand regulation or restrictions on these new satellite constellations, they should be pushing hard to developing new orbiting telescopes, now, for launch as quickly as possible.

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Perseverance’s future increasingly rocky road

11:51 am

Perseverance's uphill route
Click for original image.

Though nothing in any image so far from the Mars rover Perseverance matches the rocky terrain that the rover Curiosity has been traversing for the past two years as it climbs Mount Sharp in Gale Crater, as Perseverance has been climbing up the rim of Jezero Crater in the past few weeks it is beginning to get a hint of a future rougher road.

The photo to the right, cropped, reduced, and sharpened to post here and taken on October 20, 2024 by one of the rover’s high resolution cameras, is a good example. It looks uphill in the direction that the rover will travel. Note how as you go higher the ground appears to be more strewn with rocks and boulders. Another image, taken the same day by the rover’s high resolution camera, shows a close-up of an even more boulder-covered landscape.
» Read more

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A galaxy squashed as it plows its way through the intergalactic medium

9:21 am

A galaxy squashed by a vacuum
Click for original image.

Time for another cool image on this relatively slow day in the space news business. The picture to the right, cropped, reduced, and sharpened to post here, was taken by the Hubble Space Telescope and released today by the European Space Agency’s press department. From the caption:

Appearances can be deceiving with objects so far from Earth — IC 3225 itself [the galaxy to the right] is about 100 million light-years away — but the galaxy’s location suggests some causes for this active scene, because IC 3225 is one of over 1300 members of the Virgo galaxy cluster. The density of galaxies in the Virgo cluster creates a rich field of hot gas between them, the so-called ‘intracluster medium’, while the cluster’s extreme mass has its galaxies careening around its centre in some very fast orbits. Ramming through the thick intracluster medium, especially close to the cluster’s centre, places an enormous ‘ram pressure’ on the moving galaxies that strips gas out of them as they go.

IC 3225 is not so close to the cluster core right now, but astronomers have deduced that it has undergone this ram pressure stripping in the past. The galaxy looks as though it’s been impacted by this: it is compressed on one side and there has been noticeably more star formation on this leading edge, while the opposite end is stretched out of shape. Being in such a crowded field, a close call with another galaxy could also have tugged on IC 3225 and created this shape. The sight of this distorted galaxy is a reminder of the incredible forces at work on astronomical scales, which can move and reshape even entire galaxies!

What makes the impact on this galaxy of that intercluster medium so astonishing is that medium is so relatively empty of material. The space between galaxies in the Virgo cluster is in all intents and purposes a vacuum far more empty than any that we can create in a chamber on Earth. And yet it was enough to distort this galaxy and cause star formation on the galaxy’s leading edge.

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Young lava on the Moon?

9:08 am

Young lava on the Moon?
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Cool image time! The photo to the right, cropped and reduced to post here, was taken on November 27, 2023 by Lunar Reconnaissance Orbiter (LRO) and was today featured by the science team. From their caption:

One of the early findings from the LRO mission was the discovery of volcanic features known as Irregular Mare Patches (IMPs) scattered across the nearside. These landforms are generally considered volcanic. However, their ages are hotly debated. They may be as young as 50 million years or as old as 3.5 billion years. The Aristarchus IMP (25.045°N, 313.233°E) is one of the smallest and most enigmatic IMP. The fact that this IMP is found within the Aristarchus crater ejecta suggests it formed after the crater, which is dated at 200 million years.

Alternatively, this IMP may have formed as part of ejecta emplacement from the Aristarchus crater forming impact. However, no other crater ejecta on the Moon exhibits a similar landform.

Astronomers for decades before and since Sputnick have reported what appears to be some activity in the Aristachus region, though none of those reports have ever been confirmed. In LRO’s long mission orbiting the Moon it has not yet detected any obvious changes there, suggesting that there is little or no present activity. These patches however appear to indicate activity in the relatively recent past.

The patches however also indicate activity that seems alien. Why would the lava form in this manner, as rough patch of knobs, sometimes aligned, sometimes not?

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A different kind of chaos on Mars

2:25 pm

A different kind of chaos on Mars
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on June 23, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). I had originally chosen to feature a different picture of this spot, taken on August 1, 2024 in order to create a stereo pair, but this week the camera team featured this first photo, providing a caption.

This disrupted surface is characterized by a collection of rounded to flat-topped mounds of various sizes connected by narrow flat floors, typical of the aptly named “chaotic terrain” on Mars.

What could have caused this flat surface to break into pieces? You might imagine that a flat surface could be broken up if it was inflated or collapsed. One hypothesis is that large amounts of water were released from deep below the ground to cause the surface break up.

Normally on Mars, especially in the mid-latitudes, chaotic terrain is associated with glacial activity, suggesting that glaciers over time erode valleys along random criss-crossing fault lines to create the mesas and canyons. This patch of chaotic terrain however suggests a different formation process.
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A water sprinkler in space

11:42 am

A sprinkler in space

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken by the Hubble Space Telescope as part of a long term program to monitor changes in the R Aquarii binary star system, located about 700 light years away.

R Aquarii belongs to a class of double stars called symbiotic stars. The primary star is an aging red giant and its companion is a compact burned-out star known as a white dwarf. The red giant primary star is classified as a Mira variable that is over 400 times larger than our Sun. The bloated monster star pulsates, changes temperature, and varies in brightness by a factor of 750 times over a roughly 390-day period. At its peak the star is blinding at nearly 5,000 times our Sun’s brightness.

When the white dwarf star swings closest to the red giant along its 44-year orbital period, it gravitationally siphons off hydrogen gas. This material accumulates on the dwarf star’s surface until it undergoes spontaneous nuclear fusion, making that surface explode like a gigantic hydrogen bomb. After the outburst, the fueling cycle begins again.

This outburst ejects geyser-like filaments shooting out from the core, forming weird loops and trails as the plasma emerges in streamers. The plasma is twisted by the force of the explosion and channeled upwards and outwards by strong magnetic fields. The outflow appears to bend back on itself into a spiral pattern. The plasma is shooting into space over 1 million miles per hour – fast enough to travel from Earth to the Moon in 15 minutes! The filaments are glowing in visible light because they are energized by blistering radiation from the stellar duo.

The press release likens these filaments to the spray thrown out by a water sprinkler, and I must say that’s an apt description.

Since 2014 scientists have taken regular pictures of R Aquarii, and found that the central structures have been changing in a perceptible manner, despite their gigantic size. Below is a movie created from five photos taken from 2014 to 2023.
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NASA assembles two new panels to review its Mars Sample Return mission plans

10:38 am

NASA yesterday announced that it has assembled two new panels to review its Mars Sample Return mission plans, dubbed the strategy review and the analysis team, to be done in conjunction with the proposals the agency has already received from the private sector.

The team’s report is anticipated by the end of 2024 and will examine options for a complete mission design, which may be a composite of multiple studied design elements. The team will not recommend specific acquisition strategies or partners.

The strategy review team has been chartered under a task to the Cornell Technical Services contract. The team may request input from a NASA analysis team that consists of government employees and expert consultants.

The analysis team also will provide programmatic input such as a cost and schedule assessment of the architecture recommended by the strategy review team.

The first panel contains a mixture of NASA officials and scientists, while the second is mostly made up of NASA managers.

Whatever these panels decide, it is very clear that major changes are required to this project in order to get the Perseverance core samples on Mars back to Earth within a reasonable amount of time and at an acceptable cost. The present project design is chaotic, confused, and running significantly overbudget and behind schedule, with no indication anything will change in the near future.

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